Brake tester



June 4, 1940. o. H. FowLER BRAKE TESTER Filed Aug. 5, 1956 6Sheets-Sheet 1 I NVEN TOR. Oms-xv /fnzse ATTORNEY.

Y Julw 4, 1940. o, FQNLERA 2,203,136

BRAKE TESTER Filed Aug. 3. 41936 e sheets-sheet 2 1N VENTOR. 4Ome-1v f7.fn/Ee June 4, 1940- o. H, FowLER BRAKE TESTER Filed Aug. s'. 1936 6Sheetsheet 4 N mll m,

0 F INVENTOR. MA( OPI/E3 BY tf l.

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June 4, 1940.

o. H. ,FowLER BRAKE TESTER Filed Aug. 3. 1936 SISheetfs-Sheet 5INVENTOR. OWF/V H fan/fe June 4, 1940;

C. H. FOWLER BRAKE TESTER I N V ENTOR. L fe ATTORNEY Patented 'June1940v UNITED A STATES PATENT- OFFICE asians Balma 'rns'rna ApplicationAugust 3, 1936, Serial No. 94,095

12 Claims. The present invention relates to brake testers for testingthe brakes of automotive vehicles, and more particularly'-l to-a braketester of the impact type.

In brake testers of the impact type, a platform 5 is provided for each.of the vehicle wheels or as the platform through the braked wheels wheno the vehicle is rolled across the platforms with the brakes applied.The extent of movement of the platforms against some sort of resistancefsuch as springs, or the force tending to move the platforms is measuredwhile the vehicle traverses the same with its brakes applied, and thusan indication of brake eillciency or effectiveness of the individualwheels is obtained.

In brake testers of thev above type, provision has usually been made foroperation when a vehicle is driven in one direction only across theplatforms so that in order to make a test a vehicle must always bedriven on the platforms from the same direction. This has probablyresulted from the fact Athat such a construction is more simple, andalso that uniform operation in opposite directions would be difcult toobtain.

Accordingly it is an object ci! this invention to provide a brake testerof the type described capable of rendering measurements for! 'bothdirections of travel.

Another object of the invention is to provide a brake tester which maybe operated in both directions and in which the measurements for bothdirections are derived from a common 5 means.

' rection of extremely simple, yet rugged, construc- A further object ofthe invention is to providel a brake tester capable of operating ineither dition.

Yet another object of the invention is to provide in a brake ltester ofthe type described a single device for opposing or resisting the forceto be measured regardless of application direcshowing the platforms anddrawings are 4employed for purposes of illustra tion only and are notdesigned as a definition of the limits of the invention, reference beinghad for this purpose to the appended claims.

In the drawings, wherein like reference numerals indicate like parts:

Fig. 1 is a longitudinall section taken through one of the runways ofone form of thebrake tester substantially on the center line;

Fig. 2 is a top plan view of the brake tester w showing one platformremoved and one tread plate removed, the parts removed being above thesection line 2-2 of Fig. l;

Fig. 3 .is a transverse section taken through the tester as indicated inFig. 2 by the une 3-1 l lon which the section is taken;

Fig. 4 illustrates the electric circuit used in connection with thebrake tester;

Fig. 5 is a section taken through Fig. 2 on the line 5 5 showing ahold-down hook; 20

Fig. 6 shows an alternative construction for producing electricindications;

Fig. 7 is a longitudinal section taken through one of the runways of aslightly modified form of brake tester substantially on the centerline;`

Fig. 8 is a top plan view' of the brake tester one runway removed,

the parts removed being above the section line 8-8 oi' Fig. 7; J Fig. 9is a transverse section taken through the tester as indicated in Fig. 8by the line 9-9;

. Fig. 10 illustrates an electric circuit particularly adapted to beused in connection with the modiilc-ationof Fig. 7;

Referring more particularly to Figs. land 2, there is shown a pair ofrunways I0 and l2 each having at either end a wheel tread plate Ill vandI6. For supporting the tread plates for longi. tudinal movement, aframework is provided which is preferably sunk in a shallow pit'in thed0 iloor of a garage or other suitable location.' As shown, the frame`comprises a pair of members ll and 20 at either end of the device, eachof which is supported upon channel members 22 at either end and 24 inthe middle. The frame i mvembers il and 2l at their adjacent ends abutframe members are platforms 36, each ofwhich has on the undersidethereof parallel grooves 36 corresponding to the parallel grooves 30v inthe main support member. The balls 32 which are retained in properspaced position by :plates 30 support the platforms in anti-frictionAlongitudinal rolling relation to the main support Y Each of theplatforms carry on the members. top thereof the hereinbefore mentionedtread plates I4 and I6 which are suitably secured thereto by any commonfastening means. The tread plates are adapted to bridge the shallow pit,the same being provided with a slight ramp 40 at their remote ends andcooperating with a short stationary tread d2 over which the adjacentends i4 of the treads are adapted to slide.

'Ihe support plates i8 and 20, as previously described, have a centralslot 28 therein of sumcient width at either end to receive a short studet depending, from the platforms through the slots. These studs areprovided with a right angle bend d3 just below the support plate which,when turned transversely to the runways, holds the movable carriage fromjumping away from Ithe main support plate. i

lcarry at their lower ends an indicating device which, as shown,consists of a double-ended resister unit 56. A slider 5B adapted to makesliding. contact with the resister is fixed to the bot-v tom of the pit20. The slider is so arranged in connection with the resister that whenthe platforms arein their central position, the slider makes contactwith a central portion on the resister which may or ,may" not beinsulated. Movement of the platform in either direction, however, causesthe slider to make contact with the resister at varying pointsfunctioning like a rheostat so that by means of a suitable indicatorconnected in circuit with the resistor and slider an indication o f theextent of mowement of the platform may be obtained.

A circuit for accomplishing this result is i1- lustrated in Fig. 4wherein the battery 60 is shown, one side of which is connected to theopposite ends ofthe various resisters .5S and the other side of whiclrisconnected through 4 milliammeters, each milliainmeter being in turnconnected to a slider. The milliammeters may be conveniently arranged,as shown in Fig. 1, on a support Sti so that all indications as to therelative movement of the various platforms may be observedsimultaneously.

In Fig. 6a slightly modified form of the invenl tion is illustratedwherein a single resister rather than a double resister is employed. Astherein shown, the depending brackets 54 carry a sup-l port rod 5E onwhich is siidably threaded both a resister 5l and a slider supportsleeve 59. The resister and slider support sleeve are carried on spacedplates 63 and urged apart by a light spring 6|. Theplates 63 are locatedat either end of the spring 50 and are likewise siidably threaded on thesupport rod 55. Thus, any contraction of the spring 50 due to either arm5I moving towards the shoulders 52 at the opposite end of the slotcauses plates $3 to approach each other with such contraction andcorrespondingly causes movement of the slider relative to the runwaysand the brakesapplied as the wheels traverse the treads. The inertia ofthe vehicle will then,through the braked wheels, cause the treads tomove compressing the springs 50 and producing a change in the positionof the coni tact on the electric resistance 56, thereby'producing anindication as to the extent of movement of the tread. Since the forcewhich ,can be transmitted from the moving vehicle to the wheel treaddepends upon the extent to which the individual wheel brake iseffective, the indicator will indicate accurately the condition of thevehicle brakes. One of the features of the invention resides in the factthat the tester may be usedI by a vehicle traversing the same in eitherdirection. This results from the fact that the spring 50 may becompressed by movement of the platform in either direction. For example,if the platforms are moved to the left the spring is compressed betweenthe right .hand bracket 54 and the left hand shoulders in the slot 28.If the vehicle is moved in the opposite direction, that is tothe right,the'spring is compressed between the left hand bracket 54 and theshoulder at the Iright hand end of the slot. 'I'hus the same spring canbe used for tests in either direction and under the same circumstancesso that the accuracy of the machine cannot vary because of the directionin which it is used. In the modification of Fig. 6 the foregoingstatement is especially true since the same resister is employed formovement in either direction and must necessarily give the sameindication for the same spring compression regardless of the directionof the compressing force. While it is true that the structure of Fig. 1with a double resister may be made just as accurate, it is necessarythat the resisters be symmetrical characteristics.

Referring to Figs. 7 through 10, there is illustrated a modified form ofbrake tester,4the mechanical structural details of Figs. l'and 2 beingemployed to a large extent.v As shown particularly in Figs. '7 and 8,the brake tester is made up of a frame |00 set in a shallow pitindicated by |02, the frame being made up of a pair of flat members |04and |06 supported upon short channels |08, ||0 and ||2. Each of the intheir' electrical frame members |04 and |06 is adapted to support theforward end of the carriage being supported upon anti-friction balls |20rolling in shallow arcuate grooves |30 and |32 in the frame` member andcarriage member respectively.

As in the structure of Figs. 1 and 2, the carriage members Ill and |22are provided with central slots for Athe reception of anchoring means,guides and measuring springs. 'I'he carriage H4 is provided with anarrow slotl 'at one end 'and a Wider slot I|36 in the central portionhaving narrow slots |30 and |00 extending in opposite directions fromthe wide slot l". Along either side of the carriage members Ill *and |22are shallow grooves |44 adapted to receive lo u;

anti-frictionvballs l" and on which roll platforms l and I ll, theplatforms being provided on their underside with corresponding groovesi!! for the ders formed at either end`of the wide slot. An'

arm ill secured to the underside of the platform' extends downwardthrough the narrow slot in and is adapted: to engage the end of thespring ill. The arm also carri a resister'll which is adapted tocooperate' with a sliding contact ill secured on the carriage lllpreferably l5 in an insulated fashion. The main frame may be. providedwith which the carriage transmitted to the platform MI. In order toretain the platform i in proper position, holdan anchor bracket |62against down pins It such as shown in Fig. 5 are provided wideslot |10which has'a narrowL end in association with the slots l and |40.

The carriage i2! differs slightly from the carriage lil because of itsswivel movement. As previously described, the spring i is set in theportion i12. l An arm |14 secured to the underside of the platform illextends through the narrow slot l12and is adapted to engage a spring l,The arm also carries. a resister |16 which cooperates with a contactslider lll the latter being supported in an'insulated manner from theswivel pin |24 so that as the carriage is. swivelled the v resister andcontact have a corresponding movement. Each of the platforms l and isprovided with treads ill and il! which have ramps and cooperate with acenter stationary tread I similar to the'modification of Figs. l and 2.

The electric circuit shown in Fig. l0 is,`-ln effect,

half of the circuit shown in Fig. 4 vand operates 4o in the samemanner.'

It will appear 'from the foregoing description that the brake'tester inFigs. 'I through 10 is capable of use in the same manner as themodification of Figs. 1 to fi except that the, structure has not 4:5been adapted lfor operation in both directions.

50 upon the wheels during In the event of any misalignment of the*rearwheels or lthe'forward Wheels, one of the platforms is adapted to -moveto compensate for the that there will be no side thrust the test. Alsoduring the test for brake efficiency the relative lateral movement oftherear platforms j as the wheels roll across orl the relative swingingmovement of 'the forward platforms Ill as the wheels roll misalignmentso oslacross would 'indicate simultaneously the misalignment of thewheels. Also by swinging the forward platforms to one side or the otherand turning the steering wheels of the vehicle as the caiis drivenacross the platform to correspond .with the forward platforms, a testmay be made which will indicate the operation of the brakes while the.vehicle is rounding a turn. Also under these conditions, the alignmentof the forward wheels when steered away from straight ahead 05 can beobserved. Also should it not be practical to guide the vehicle during animpact test along the brake te'ster with the forward platforms,4

/ turned, it will appear obvious that tests can, be

. effected by pushing or pulling the vehicle over' 70 the testingplatforms by sorne outside force, for

example, another vehicle. l

There is thus provided a novel impact brake tester capable of use byvehicles traversing the same in either direction, the structure thereofu being 4:extremely six'nple,` and .the measurements lil may abut when aforce is thereto but maybe embodied in various other'mechanical-arrangements and forms. As various changes in constructionand arrangement may be made without departing from the spirit of the vinvention as will be apparent to those skilled in the art, referencewill be had to the appended claims for a definition of the limits oftheinven- What is claimed is: t l. An impactautomotive vehicle brake testercomprising a supporting frame, a longitudinally movable platformthereon. there being a slot in said frame having a-centrally enlargedportion, a yielding element in said enlarged portion, and arms dependingfrom said platform at either end of said yielding element.

2; An impact automotive vehicle brake tester comprising a supportingframe, a longitudinally movable platform thereon, there being a slot insaid frame having a centrally enlarged portion,

a yielding element in said enlarged portion, arms depending from saidplatform at either end of said yielding'element, and means forindicating the extent of 'movement of said platform.

3. Animpact automotive vehicle brake tester comprising a supportingframe, a platform .thereon longitudinally movable in either direc-tionfrom a central normal position, anti-friction means for supporting saidplatform,` there being a central 7longitudinally-extending sloijl insaid frame having a central portion thereof of increased width, a springpositioned in said central portion, and adapted at either end to bearagainst the slot shoulders formed by the increasedy width, armsdepending from said platform into the narrow portions of saidslotadapted to engage the spring ends, and means cooperating with the slotto restrain the platform from movements other than longitudinal.

4. An impact automotive vehicle brake tester comprising a supportingframe, a platform theres on longitudinally movable in either directionfrom a centralnormal position, anti-friction means for supporting saidplatform, 'there being a central longitudinally-extending slot in saidframe having a central portion thereof of increased width. a springpositioned in said central rtion, and adapted at either end to bearagainst he slot shoulders formed 'by the increased width, arms dependingfromV said platform into the narrow portions of said slot and adapted toengage the spring ends, and means for indicating portion, and adapted ateither end to bear against the slot shoulders formed by the increasedwidth.'

arms depending from said platform into the narrow portions of said slotadapted to engage the spring ends, means cooperating with the slot torestrain the platform from movements other than longitudinal, and anelectrical indicating] means comprising a resistance unit supported fromsaid, arms, a stationary slider for slidably contacting said unit, andelectrical circuit means including a source of electrical energy and anelectrical current indicating instrument. 6. An impact automotivevehicle-brake tester comprising a supporting frame, a platform thereonlongitudinally movable in either direction from a central normalposition, anti-friction means for supporting said platform, there beingaV central longitudinally-extending slot in said frame having a centralportion thereof of increased width, a spring positioned in said centralportion, and adapted at either end to bear against the slot shouldersformed by the increased width, arms depending from said platform intothe narrow portions of said slot adapted to engagethe spring ends, meanscooperating with the slot to restrain the platform from movements' otherthan longitudinal, and an electrical indicating means comprising adouble resistance unit supi ported between said arms and a stationaryslider contact adapted to slide from a midpoint on said, unit towardseither end upon movement of said platform in either direction.

r7. An impact automotive vehicle brake tester 'comprising a supportingframe, longitudinallyv movable wheel platforms thereon movable `from acentral normal position, af'spring nested in a rectangular aperture insaid frame member beneath each vof said platforms, there being alongitudinally-extending narrow slot in the frame meunier extending)ineach direction from the aperture, a pair of/ arms depending from theplatform through the slots at opposite ends of the spring, an indicatingunit for determining deection of said spring, and means for supportingthe indicati/ng unit from thearms.

8. In an impact brake tester for automotive vehicles, a supportingmember, a platform adapted for movement longitudinally with respect tothe member, an anchor for the member adapted to resist longitudinalmovement thereof', a slot insaid member having narrow portions and acentral wide portion, a spring in saidwide portion,

an arm secured tosaid platform and extending through one of the narrowportions of said slot and adapted to engage one end of said spring, andmeans secured to said platform and depending through the other narrowportion of said slot for restricting the platform to longitudinalmovement with respect to the slot.

9. In an impact brake tester for automotive vehicles, a supportingmember', a platform adapted for movement longitudinally with respect tothe member, an anchor for the member adapted to resist longitudinalmovement thereof, a slot L in said member having narrow portionsv and ascentral wide portion, and shoulders at the juncture of the narrow andwide portions, a spring nested in the wide portion and resting againstsaid shoulders at either end, an arm secured to v said platforml andextending through one of the narrow portions of said slot and adapted toengage one end of said spring, and means including a pin secured to saidplatform and depending through the other narrow portion of said slot forrestricting the platform to longitudinal movement with respect to theslot.

10. An impact automotive vehicle brake tester comprising a supportingframe, a platform thereon longitudinally movable with respect to saidframe, anti-friction means for supporting said platform, there being acentral longitudinally extending slot in said frame having a centralportion thereof of increased width, a spring positioned in said centralportion, and adapted at either end to bear against the` slot shouldersformed by the increased width, an arm depending from saidv platforminto'a narrow portion of cooperating with the slot to restrain theplatform from movements other than longitudinal, and an electricalindicatingmeans comprising a resistance supported at one end by saidarm. and a relatively stationary electrical slider contact adapted toslide on said resister upon longitudinal movement of the platform.

11. An impact automotive vehicle brake tester comprising a supportingframe, a longitudinally movable platform thereon, there being alongitudinally extending slot in said frame having a centrally enlargedportion. a yielding element in said enlarged portion and engaging theend shoulders formed by the enlarged portion, an arm depending from theplatform through a narrow portion of said slot and adapted to engage anend of said element, and means extending 'said slot to engage an end ofthe spring, means through said slot along a narrow portion thereof tolongitudinal movethere being a longitudinally-extending slot in saidframe and located in substantial alignment with said spring, the slotextending inopposite.

directions from both ends of said-spring, and means rigidly connectedtosaid platform and cooperating with said slot, said means abuttingopposite ends'oi said spring for yieldably resisting longitudinalmovement of said platform in opposite directions from acentralnormalposition and restraining said platform from movement other thanlongitudinal.

ownN H. Fo'wLn'a.

